Evaluation of rules against a container of information or data is a common process in many computer applications. For example, content-based publish/subscribe systems have become widely used and in such systems, subscribers specify the content that they are interested in by creating rules with conditions. A primary goal of such a system is to determine what subscriptions match with a given data element or message, based on evaluation of the rules against input data or messages. A core element of the technology that enables an efficient operation for matching a large number of conditions with corresponding data is a rules evaluation engine, or simply, a rules engine.
In general, database technology can be leveraged to provide an efficient rules engine for evaluating a massive number of rules against massive amounts of data. Technological advances have been made in this area of database technology; however, the solution is usually intrinsically tied to the specific problem being solved.
Many computer applications or application features can benefit from having flexibility with respect to their behavior relative to externally specified conditions. Such conditions are often used to customize an application or to deploy an application efficiently. The conditions can change over time and, therefore, may need to be evaluated frequently.
Based on the foregoing, it is clearly desirable to provide a rules engine based on a database management system, which accommodates service to applications external to a database server.